Quote Originally Posted by Art View Post
Thought I'd better post that there is an error in the LED matrix schematic.
The 18 transistors should all be connected to + 5 Volts, not Gnd.
Cheers, Art.
What's connected to +5V? Not the emitter. Not on an NPN.

If it's a PNP the load goes in the emitter (emitter follower, and doesn't need a base resistor) or in the collector (and needs the resistor). It's drawn now as an NPN open collector. If it is an NPN and *something* is connected to +5 it's the collector (the only time I've ever connected a postive supply rail to the emitter of an NPN has been when designing very high speed switches and we ain't going there)...

I've got all but the switches and ICSP header and related components in place. You can see the top layer here: http://www.scarydesign.com/144/144topview.pdf It hasn't been optimized for size yet or mounting holes etc.

The pads look a little odd because you can use TH or SMD components. I'll wait to do more until this has been worked out...

Mike Tripoli